Another Speedo Question

phillyskip · Jul 16, 2014

If you want to check if a speedometer on a 72 Norton is working, what direction should you spin the cable on the speedo drive end? Clockwise or counter clockwise? Thanks ,Skip

auldblue · Jul 16, 2014

Hi

If my memory is ok it's clockwise, but I was told by Arthur Gagg not to spin it on a drill. Never said why. Anyway just stick it on a bike!
J

phillyskip · Jul 16, 2014

My gauge is not working and I don't know if its the gauge or speedo drive?

auldblue · Jul 16, 2014

Hi

I had the same thing , took the speedo drive down , train wreck.
The end of the cable is worth a good look also.
J

pete.v · Jul 16, 2014

phillyskip said:
My gauge is not working and I don't know if its the gauge or speedo drive?

Or the cable.
Pull/remove the cable from the gauge and spin the tire. You will see the direction of rotation(don't want to be guessing) and you will see the internal turning or not.
If cable is turning proper, with the direction of rotation now known, you can use the right sized square bit to check the guage with a drill. My GUESS is counterclockwise.

Report.

auldblue said:
Hi, I am writing words, more words, followed by somemore words and ending with words J

Hey auldblue, you wouldn't be related the Mr. Yates would you? There's a remarkable resemblance.

auldblue · Jul 16, 2014

pete.v said:
phillyskip said:

My gauge is not working and I don't know if its the gauge or speedo drive?

Click to expand...

Or the cable.
Pull/remove the cable from the gauge and spin the tire. You see the direction of rotation(don't want to be guessing) and you will see it is turning proper. Report.

auldblue said:

Hi, I am writing words, more words, followed by somemore words and ending with words J

Click to expand...

Hey auldblue, you wouldn't be related the Mr. Yates would you? There's a remarkable resemblance. Empty posts!

Cheers Pete , your absolutely bang on, sorry to go off thread I was looking at the photos of your commando, are you running a mag at the moment? It looks well.

J

kerinorton · Jul 16, 2014

phillyskip said:
My gauge is not working and I don't know if its the gauge or speedo drive?

PULL THE INNER OUT OF THE CABLE AND SHOVE IT IN THE SPEEDO DRIVE [ OR DISCONNECT FROM THE SPEEDO , ROTATE THE WHEEL AN TRY TO STOP THE CABLE TURNING. ]. if ITS WORKING YOU WONT BE ABLE TO STOP THE CABLE TURNING. ROTATION OF CABLE IS IN SAME DIRECTION SPEEDO WORKS. SO FROM THE SPEEDO END IT IS CLOCKWISE [ LOOKING FROM FACE OF SPEEDO DOWN THROUGHTOTHE DRIVERR] LOOKING FROM THE SPEEDODRIVE IT IS ANTICLOCKWISE.

phillyskip · Jul 17, 2014

Thanks all for the info .I'm going to the shop to perform some tests,I'll report back.....Skip

baldy · Jul 17, 2014

Skipper,

Easiest way I have found to spin the speedo is to use the tach cable and drive gear with a drill on anti-clockwise (reverse). The tach drive gear end fits nicely on a drill chuck.

phillyskip · Jul 17, 2014

Thanks!

wjrich · Jul 17, 2014

Phillyskip- let me know which way the drill goes. I've got to go through the same process on my MK III this weekend.

auldblue · Jul 17, 2014

Arthur Gagg says don't do it with a drill. But he is a funny old geezer, been repairing clocks all his life I think.

J

wjrich · Jul 18, 2014

Tested the speedo head using a drill set in reverse., and speedo seemed to respond ok.
My next move is to look at the drive. I took the wheel off, removed chain guard, released sprocket. How do you separate the drive from the axle? (Mk III)

wjrich · Jul 18, 2014

auldblue said:
Hi

I had the same thing , took the speedo drive down , train wreck.
The end of the cable is worth a good look also.
J

Once I able to remove the drive and see it as you are looking at your drive, what in your picture is showing what's wrong?

auldblue · Jul 18, 2014

That is the guts of the drive ,the two lugs that engage with the notches on the wheel spin but do not spin the worm drive, you can just see it in the picture. It's not hard to take it to bits I did that one about 18 months ago and cannt quite remember , it's a age thing. Basically it's worn out. I have heard of someone who did a home fix , involved drilling and riveting .

If you turn the two lugs and they are stiff and notchy, try cleaning it and a spot of grease , I think not greasing them and cleaning it regularly is the part of the problem.if it's stiff and notchy after cleaning ,I recon it's pumped.
J

wjrich · Jul 19, 2014

Not sure how to get the drive off the axle- seems pretty securely attached- any tips to remove it?
It does feel a bit notchy, may just need a good cleaning.

texasSlick · Jul 19, 2014

The admonition not to use a drill, is because most drills turn CW. Tell some guy it is OK if the drill is reversible, and set to CCW, and Murphy's Law says he will use it in CW mode.

Most failures in the speedo gearbox are due to the internal worm wearing down to nothing. With the gearbox removed from the bike, and with the cable attached to the gearbox, spin the drive dogs with the fingers while holding the end of the speedo cable to offer resistance. If no rotation of cable, the worm is shot.

There was a thread recently on home repair of gearbox posted on this Forum. IMO, a new Smiths is the way to go....avoid the knock-offs.

Slick

Onder · Jul 19, 2014

I find that the two dogs are often shot more than anything else. This comes from improper fitting
when bolting up the wheel to the swinging arm.
You say avoid the knockoffs. Fine. Ive not seen anything but, never saw a new made Smiths on offer.
Your source?

wjrich · Jul 19, 2014

Tried to post this earlier- not sure where it went.

Read some great threads on the speedo drive box, but still don't know ho to detach it from the sprocket. Seems like it is fixed to the axle, but I can't see how to detach it. Any ideas out there?

Guido · Jul 19, 2014

wjrich said:
Tried to post this earlier- not sure where it went.

Read some great threads on the speedo drive box, but still don't know ho to detach it from the sprocket. Seems like it is fixed to the axle, but I can't see how to detach it. Any ideas out there?

The drive just slips off. What you have there is a rusted, frozen GB. Try some PB Blaster or other penetrant to loosen it up and then just drive the axle bolt through.
That box looks shot.

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